Ethan Crumbley showed off ammunition during class at Oxford High School the day before he allegedly shot and killed four fellow students, and a lawsuit amended and re-filed Tuesday alleges school leaders knew he did so and failed to act. The suit accuses Oxford officials of neglecting to report Crumbley to Child Protective Services despite threatening to do so based on his disturbing behavior, including researching ammunition on his phone and drawing guns on his math homework. The day before the grim display, Crumbley had brought a severed bird head to school in a jar full of yellow liquid and left it on a toilet paper dispenser in a boys’ bathroom. Nora Hanna, an attorney for the plaintiffs, told the Detroit Free Press, “The school was on alert about Ethan. There are a million things that they could have done.”